    * {
        margin: 0;
        padding: 0;
    }
    
    body {
        background-color: #f3f5f7;
    }
    
    li {
        list-style: none;
    }
    
    a {
        text-decoration: none;
    }
    /* 去除input选中后的黑色边框 */
    
    input:focus {
        outline: none;
    }
    
    .w {
        width: 1200px;
        margin: auto;
    }
    
    .fl {
        float: left;
    }
    
    .fr {
        float: right;
    }
    
    .clearfix:after,
    .clearfix:before {
        content: "";
        display: table;
    }
    
    .clearfix:after {
        clear: both;
    }
    
    .clearfix {
        zoom: 1;
    }
    
    .header {
        height: 42px;
        margin: 30px auto;
    }
    
    .header .logo {
        width: 198px;
        height: 42px;
    }
    /* 导航栏 */
    
    .header .nav {
        margin-left: 40px;
        height: 42px;
    }
    
    .header .nav ul li {
        float: left;
        margin: 0 15px;
    }
    
    .header .nav li a {
        display: block;
        height: 42px;
        line-height: 42px;
        padding: 0 10px;
        font-size: 18px;
        color: #050505;
    }
    
    .header .nav ul li a:hover {
        border-bottom: 2px solid #00a4ff;
        color: #00a4ff;
    }
    /* 搜索 */
    
    .header .search {
        width: 410px;
        height: 42px;
        margin-left: 50px;
    }
    
    .header .search input {
        padding-left: 15px;
        background-color: transparent;
        width: 344px;
        height: 40px;
        border: 1px solid #00a4ff;
        border-right: 0;
    }
    
    .header .search button {
        float: right;
        background: url('./images//search.png') no-repeat;
        height: 42px;
        width: 50px;
        border: 0;
    }
    /* 用户 */
    
    .header .user {
        margin-right: 30px;
        height: 42px;
        font-size: 14px;
        color: #666;
        line-height: 42px;
    }
    
    .user-name {
        display: block;
        overflow: hidden;
        max-width: 110px;
        text-overflow: ellipsis;
        white-space: nowrap;
    }
    /* banner */
    
    .bannerContent {
        background: #1c036c;
        height: 420px;
    }
    
    .bannerContent .w {
        background: url(./images/banner.png) no-repeat top center;
        height: 420px;
    }
    
    .bannerContent .banner .subnav {
        width: 190px;
        height: 420px;
        background: rgba(0, 0, 0, .3);
    }
    
    .bannerContent .banner .subnav ul li {
        padding: 0 20px;
        height: 45px;
        line-height: 45px;
    }
    
    .bannerContent .banner .subnav ul li span {
        float: right;
    }
    
    .bannerContent .banner .subnav ul li a {
        display: block;
        color: #fff;
        font-size: 14px;
    }
    
    .bannerContent .banner .subnav ul li a:hover {
        color: #00a4ff;
    }
    
    .courseContent {
        width: 230px;
        height: 300px;
        margin-top: 50px;
    }
    
    .courseContent>h3 {
        background: #9bceea;
        height: 48px;
        line-height: 48px;
        text-align: center;
        font-size: 18px;
        color: #fff;
    }
    
    .courseContent .course {
        background-color: #fff;
        height: 252px;
        padding: 0 20px;
    }
    
    .courseContent .course ul li {
        padding: 14px 0;
        border-bottom: 1px solid #ddd;
    }
    
    .courseContent .course ul li h4 {
        font-size: 16px;
        color: #4e4e4e;
    }
    
    .courseContent .course ul li p {
        font-size: 12px;
        color: #a5a5a5;
    }
    
    .courseContent .course .more {
        display: block;
        margin-top: 5px;
        height: 38px;
        border: 1px solid #00a4ff;
        text-align: center;
        /* 行高会继承给子元素 */
        line-height: 38px;
        color: #00a4ff;
        font-size: 16px;
        font-weight: 700;
    }
    /* 精品推荐 */
    
    .recommend {
        margin-top: 10px;
        box-shadow: 0 2px 3px 3px rgba(0, 0, 0, .1);
        height: 60px;
        line-height: 60px;
        background-color: #fff;
    }
    
    .recommend>h3 {
        margin-left: 30px;
        color: #00a4ff;
        font-size: 16px;
    }
    
    .recommend .goods-item {
        margin-left: 30px;
    }
    
    .recommend .goods-item li {
        float: left;
    }
    
    .recommend .goods-item li a {
        padding: 0 30px;
        border-left: 1px solid #ccc;
        color: #050505;
        font-size: 16px;
    }
    
    .recommend .goods-item li a:hover {
        color: #00a4ff;
    }
    
    .recommend .mod {
        margin-right: 30px;
        color: #00a4ff;
        font-size: 14px;
    }
    /* 左侧边栏 */
    
    .left-sidebar {
        position: sticky;
        float: left;
        top: 270px;
        width: 180px;
        height: 425px;
        background: #fff;
        /* position: fixed; */
        /* right: 50%; */
        /* margin-right: 625px; */
    }
    
    .left-sidebar ul {
        margin-top: 15px;
    }
    
    .left-sidebar ul li {
        padding: 0 25px;
    }
    
    .left-sidebar ul li a {
        display: block;
        height: 38px;
        line-height: 38px;
        color: #000;
        font-size: 14px;
    }
    
    .left-sidebar ul li .active {
        color: #00a4ff;
    }
    /* 精品推荐核心部分 */
    
    .box {
        margin-top: 35px;
    }
    
    .box .box-hd {
        height: 40px;
        line-height: 40px;
    }
    
    .box .box-hd h3 {
        font-weight: normal;
        color: #494949;
        font-size: 20px;
    }
    
    .box .box-hd a {
        color: #a5a5a5;
        font-size: 12px;
        margin-right: 30px;
    }
    
    .box .box-hd a:hover {
        color: #00a4ff;
    }
    
    .box .box-bd {
        width: 1225px;
    }
    
    .box .box-bd ul li {
        position: relative;
        float: left;
        width: 228px;
        height: 270px;
        margin-right: 15px;
        background-color: #fff;
    }
    
    .box .box-bd li:hover {
        box-shadow: 2px 2px 5px 2px rgba(0, 0, 0, .3);
    }
    
    .box .box-bd ul li a .bd-img {
        /* 图片本身宽度大于盒子宽度 */
        width: 100%;
    }
    
    .box .box-bd ul li a .icon-img {
        position: absolute;
        right: 0;
        top: 5px;
    }
    
    .box .box-bd ul li a h4 {
        padding: 25px 20px 20px 25px;
        font-weight: normal;
        color: #050505;
        font-size: 14px;
    }
    
    .box .box-bd ul li a .info {
        padding-left: 25px;
        color: #999999;
        font-size: 12px;
    }
    
    .box .box-bd ul li a .info span {
        color: #ff7c2d;
    }
    /* 编程入门部分 */
    
    .programContent {
        margin-top: 40px;
    }
    
    .programContent .hd {
        height: 40px;
    }
    
    .programContent .hd h3 {
        color: #494949;
        font-size: 20px;
        font-weight: normal;
    }
    
    .programContent .hd ul {
        margin-left: 280px;
    }
    
    .programContent .hd ul li {
        float: left;
    }
    
    .programContent .hd ul li a {
        display: block;
        margin-top: 5px;
        padding-left: 70px;
        font-size: 16px;
        color: #868686;
    }
    
    .programContent .hd ul li .active {
        color: #00a4ff;
    }
    
    .programContent .hd .more {
        margin-top: 5px;
        margin-right: 30px;
        color: #a5a5a5;
        font-size: 12px;
    }
    
    .programContent .hd .more:hover {
        color: #00a4ff;
    }
    
    .programContent .bd .second_floor_right .advertising_img {
        height: 100px;
    }
    
    .programContent .bd .second_floor_right .bd_box {
        margin-top: 22px;
    }
    
    .programContent .bd .second_floor_right .bd_box li {
        float: left;
        margin-right: 15px;
        width: 228px;
        height: 270px;
        background: #fff;
    }
    
    .programContent .bd .second_floor_right .bd_box li:last-child {
        margin-right: 0;
    }
    
    .programContent .bd .second_floor_right .bd_box li:hover {
        box-shadow: 2px 2px 5px 2px rgba(0, 0, 0, .3);
    }
    
    .programContent .bd .second_floor_right .bd_box li a .bd-img {
        width: 100%;
    }
    
    .programContent .bd .second_floor_right .bd_box li a h4 {
        padding: 25px 15px 20px 25px;
        font-size: 14px;
        color: #050505;
        font-weight: normal;
    }
    
    .programContent .bd .second_floor_right .bd_box li a .info {
        padding-left: 25px;
        font-size: 12px;
        color: #999;
    }
    
    .programContent .bd .second_floor_right .bd_box li a .info span {
        font-size: 12px;
        color: #ff7c2d;
    }
    /* 底部 */
    
    .footer {
        margin-top: 40px;
        width: 100%;
        height: 240px;
        background: #fff;
        overflow: hidden;
    }
    
    .footer .footerContent {
        margin-top: 30px;
    }
    
    .footer .footerContent .footer-info .corpyright {
        padding: 25px 0 20px 0;
        color: #666666;
        font-size: 12px;
    }
    
    .footer .footerContent .footer-info .app {
        border: 1px solid #00a4ff;
    }
    
    .footer .footerContent .footer-info .app a {
        display: block;
        padding: 15px 30px;
        color: #00a4ff;
    }
    
    .footer .footerContent .footer-info .app a:hover {
        color: #fff;
        background: #00a4ff;
    }
    
    .footer .footerContent .links {
        margin-right: 40px;
    }
    
    .footer .footerContent .links dl {
        float: left;
        margin-left: 140px;
    }
    
    .footer .footerContent .links dt {
        margin-bottom: 15px;
        color: #333333;
        font-size: 16px;
    }
    
    .footer .footerContent .links dd {
        line-height: 21px;
    }
    
    .footer .footerContent .links dd a {
        color: #333333;
        font-size: 12px;
    }
    
    .footer .footerContent .links dd a:hover {
        color: #00a4ff;
    }